The proteins to be studied include iron-sulfur proteins, proteases, flavoproteins and other metalloproteins. Our approach to the investigation of proteins is as follows. I. Isolation, purification and characterization of a protein with a specific function. II. Sequence determination of a protein. III. Determination of the 3D- structure by X-ray diffraction techniques of the crystalline protein. With these two basic structural data on hand, we propose to pursue: a. structure-function investigations; b. detailed physicochemical studies; c. and the chemical synthesis of some of the proteins. Our laboratory is concerned primarily with the primary structure of the proteins. We are not carrying out the X-ray investigations but we are working together closely with the laboratory of Dr. Lyle Jensen at the University of Washington, Dr. Herriot at the University of Washington and Dr. Martha Ludwig at the University of Michigan. We have provided proteins in some cases and in other cases, the sequence work and the X- ray work are proceeding hand in hand.